The soluble (Pro) renin receptor does not influence lithium‐induced diabetes insipidus but does provoke beiging of white adipose tissue in mice

Earlier we reported that the recombinant soluble (pro) renin receptor sPRR‐His upregulates renal aquoporin‐2 (AQP2) expression, and attenuates polyuria associated with nephrogenic diabetes insipidus (NDI) induced by vasopressin type 2 receptor (V2R) antagonism. Patients that receive lithium therapy develop polyuria associated NDI that might be secondary to downregulation of renal AQP2. We hypothesized that sPRR‐His attenuates indices of NDI associated with lithium treatment. Eight‐week‐old male C57/BL6 mice consumed chow supplemented with LiCl (40 mmol/kg diets) for 14 days. For the last 7 days mice received either sPRR‐His [30 μg/(kg day), i.v.; sPRR] or vehicle (Veh) via minipump. Control (Con) mice consumed standard chow for 14 days. Compared to Con mice, 14‐d LiCl treatment elevated water intake and urine volume, and decreased urine osmolality, regardless of sPRR‐His or Veh administration. These data indicate that sPRR‐His treatment does not attenuate indices of NDI evoked by lithium. Unexpectedly, epididymal fat mass was lower, adipocyte UCP1 mRNA and protein expression were higher, and multilocular lipid morphology was enhanced, in LiCl‐fed mice treated with sPRR‐His versus vehicle. The beiging of white adipose tissue is a novel metabolic benefit of manipulating the sPRR in the context of lithium‐induced NDI.